1. Field of Invention
This invention generally relates to systems and method for annotating three-dimensional electronic documents.
2. Description of Related Art
Page annotation of documents including books, magazines, journals, textbooks, photo albums, maps, periodicals, or the like, is a common technique performed by readers and viewers of these documents. The page annotation feature is highly desirable to the readers and the viewers because this feature provides the readers and the viewers with the ability to mark the documents with text notes, handwritten notes, bookmarks, highlights and/or the like.
Although many of these documents have been traditionally presented in paper format, electronic formats of these documents have become widely available due to numerous developments in the computer related fields, i.e. the Internet. With the increasing growth of electronic documents, the readers and the viewers still find the page annotation feature highly desirable. Therefore, some annotation tools for two-dimensional electronic documents have been provided.
For example, Schilit, Price, and Golovchinsky describes a research prototype called XLibris® used to display two-dimensional electronic document pages and support free-form annotations, which runs on a tablet computer and accepts pen input. By using the pen, the user can scribble notes, draw figures, and highlight text. The user also has the option of changing the color of the pen and/or selecting between a wide pen and a narrow pen.
PCT Patent WO0,142,980 describes an annotation tool for annotating two-dimensional electronic documents. PCT Patent WO0,142,980 describes that “the annotations are stored separately from the viewed document pages but are correlated with the pages such that when a previously annotated page is revisited, annotations related to that page are retrieved and displayed on top of the page as an ‘ink’ layer.” By using the stylus, the user can highlight certain parts of the two-dimensional document in translucent colors or mark opaque annotations on the page, in a way very similar to XLibris. To display the annotations, the “pixel blending function blends pixels from a document page with corresponding pixels from an annotation or ‘ink’ layer mapped to that document page, and generates a blended pixel image that is displayed as an annotated document page.”
PCT Patent No. WO0,201,339 also describes an annotation tool for annotating two-dimensional electronic documents. PCT Patent No. WO0,201,339 describes a technique which “analyzes the ink for each annotated pixel and renders the color and brightness of each pixel based on the original pixel color and the added annotation color so as to appear as physical ink would typically appear if similarly applied to physical paper.”
Although using two-dimensional electronic annotation tools in three-dimensional electronic documents is conceivable, visualization and technical implementation problems result when the annotation tools created for the two-dimensional electronic documents are applied to three-dimensional electronic documents. Zinio Reader®, developed by Zinio Systems Inc., located at http://www.zinio.com and Adobe Acrobat® are two examples of annotation tools.
Adobe Acrobat® includes one example of a two-dimensional electronic annotation tool that allows selected portions of the electronic document to be highlighted. However, if the two-dimensional electronic highlighter annotation tool is applied to a three-dimensional electronic document, then difficulty in defining the highlight area and the visualization of the highlighting ink is presented.
For example, to capture and display pen-based annotations in three-dimensions is different from capturing and displaying pen-based annotations in two-dimensions. Specifically, in two-dimensions, translation of the user input from the computer screen to the page and updating the appearance of the page is relatively straightforward. On the other hand, in three-dimensions, three-dimensional transformations must be employed to determine where on the page the user wants to place an annotation and the three-dimensional parameters of the page must be modified in order to show the annotation in the rendered image. Therefore, it is desirable to create annotation tools specifically designed to annotate three-dimensional electronic documents. Although programs that alter three-dimensional objects exist, annotation tools to annotate three-dimensional electronic documents are limited.
For example, Hanrahan and Haeberli describe a three-dimensional electronic paint program that uses a technique to paint surfaces of three-dimensional electronic objects in “Direct WYSIWYG Painting and Texturing on 3D Shapes,” Proceedings of the ACM SIGGRAPH'90 Conference, pages 215–223. Based on what is displayed on the computer screen, the user manipulates the parameters, i.e., diffuse color, specular color, and surface roughness, used to shade the surfaces of the three-dimensional object. The paint brush strokes specified by the user are transformed from the screen space to the texture space of the object to update the texture data. As a result, the appearance of the 3D surfaces is modified. Although the three-dimensional paint program paints surfaces of three-dimensional objects, the three-dimensional paint program is not an annotation tool used to annotate a three-dimensional electronic document.